Question: ${5 \div 0.4 = {?}}$
Answer: $ {5 \div 0.4 = 5 \div \dfrac{4}{10}} $ $ {\phantom{5 \div 0.4} = 5 \div \dfrac{2}{5}} $ Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. $ {5 \div \dfrac{2}{5} = 5 \times \dfrac{5}{2}} $ $ {\phantom{5 \div \dfrac{2}{5}} = \dfrac{5 \times 5}{2}} $ $ {\phantom{5 \div \dfrac{2}{5}} = \dfrac{25}{2}} $ $ {\phantom{5 \div \dfrac{2}{5}} = 12.5} $